The present invention relates to an electric control apparatus for a carburetor adapted to internal combustion engines, and more particularly to an electric control apparatus for a carburetor which comprises a body formed therein with an intake conduit, a flow control element axially movable within a passage such as an air bleed passage in the body for controlling the cross-sectional area of the passage in accordance with axial displacement thereof, and a stepper motor mounted on the body for effecting the axial displacement of the flow control element in accordance with the operating condition of the engine.
In such an electric control apparatus as described above, it is required to precisely control operation of the stepper motor in response to various instantaneous changes of the operating condition of the engine. It takes, however, a time inevitably for each forward or backward step motion of the stepper motor. Additionally, the time for each step motion changes in accordance with various loads acting on the stepper motor. For these reasons, if the stepper motor was applied with an electric control signal for backward or forward step motion during forward or backward motion thereof, a desired control of the stepper motor would not be effected.